Treating Heart Tissue

ABSTRACT

Some embodiments of a system or method for treating heart tissue can include a catheter device that provides a user with the ability to perform a number of heart treatment tasks (before, during, and after a cardiac surgery or a percutaneous coronary intervention). In particular embodiments, the catheter device can be used to (i) precondition heart muscle tissue before the heart is isolated from the circulatory system, (ii) deliver cardioplegia into the coronary sinus during the cardiac surgery when the heart is isolated from the circulatory system, and (iii) control the blood flow through the heart after the heart is reconnected with the circulatory system. In some embodiments, the catheter device can perform some or all of: (i) intermittently occluding the coronary sinus, (ii) delivering a treatment fluid into the coronary sinus, and (iii) monitoring a flow rate of blood passing from the coronary sinus to the right atrium.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This is a division of U.S. patent application Ser. No. 12/788,016 filedon May 26, 2010 and entitled “Treating Heart Tissue,” the contents ofwhich are fully incorporated herein by reference.

TECHNICAL FIELD

This document relates to systems and methods that are configured totreat heart tissue, for example, during an open heart surgical operationor during a percutaneous coronary intervention.

BACKGROUND

During some cardiac surgeries, the heart can be isolated from thecirculatory system while the patient is connected to a heart-lungmachine (also known as a perfusion machine). The heart-lung machineprovides an extracorporeal circuit to oxygenate and pump blood throughthe patient's circulatory system. Typically, a venous catheter isinserted into the right atrium and drains blood returning from the bodyinto the extracorporeal circuit of the heart-lung machine. Also, anarterial cannula is inserted into the aorta, so that oxygenated bloodfrom the heart-lung machine can be pumped back into the patient'scirculatory system. After these catheters are in place, the aorta may becross clamped between the arterial cannula and the heart to therebyprevent blood from flowing backwards into the heart. Such a procedureprovides oxygenated blood to all areas of the body except the heart. Inorder to prevent degradation of the heart muscle tissue during thesurgery, a cold cardioplegic fluid can be infused into the heart to bothcool the heart and stop it from beating. After the initial infusion, theheart may be periodically reperfused to maintain thereduced-temperature, dormant state of the heart.

The cardioplegia solution may be administered in an antegrade manner(through arteries in the normal direction of blood flow), in aretrograde manner (through veins opposite the normal blood flowdirection), or in a combination of retrograde and antegradeadministration. The cardioplegic solutions can temporarily stop theheart by interfering with the conduction of the heart's natural electricsignals that cause heat beats.

Retrograde cardioplegia is conventionally administered by inserting aballoon catheter into the coronary sinus, inflating the balloon, andperfusing the cardioplegic solution backwards through the coronaryveins. Some catheters for retrograde coronary sinus perfusion (RCSP) mayemploy a manually inflating balloon that is filled through an inflationlumen. While the balloon is inflated, the flow of blood or solution fromthe coronary sinus to the right atrium is blocked.

During the period of time that the heart is deprived of normal bloodflow, there is a risk that a portion of the heart muscle tissue may bedamaged (such as ischemic heart muscle tissue). Further, after thecardiac surgery in completed and the aorta is unclamped to restorenormal blood flow to the heart, the immediate rush of blood through theheart muscle tissue can cause additional damage to the heart muscletissue to a point that normal blood flow does not return through theischemic portion of the heart muscle tissue.

Further, in some cases, the heart may be treated without the need for anexternal blood pump of a heart-lung machine. For example, during apercutaneous coronary intervention, a blockage in a coronary artery maybe repaired or removed with a stent or angioplasty balloon that ispercutaneously delivered. The blockage in the coronary artery can resultin a loss of blood flow through a portion of the heart muscle tissue,thereby creating an area of damaged or ischemic heart muscle tissue.

SUMMARY

Some embodiments of a system or method for treating heart tissue caninclude a multi-functional catheter device that serves to protect orrestore heart muscle tissue from damage during an open heart surgery (incombination with a heart-lung machine), an off-pump cardiac surgery, ora percutaneous coronary intervention procedures. The catheter device canbe used, for example, in a process that intermittently occludes thecoronary sinus, delivers cardioplegia or blood into the coronary sinus,or a combination thereof.

Particular embodiments described herein include of a system of methodthat provides a surgeon or other user with the ability to perform anumber of heart treatment tasks (before, during, and after cardiacsurgery) while a balloon device remains inflated in the coronary sinus.In particular, the catheter device can be readily used to preconditionheart muscle tissue (locally) before the heart is isolated (or clamped)from the circulatory system. For example, the catheter device can beequipped to provide pressure-controlled intermittent coronary sinusocclusion (PICSO) treatment to the heart so as to precondition the heartmuscle tissue with redistributed venous blood flow. Also, the catheterdevice can be employed to deliver cardioplegia (e.g., pulsatileretrograde cardioplegia in particular embodiments) into the coronarysinus during the cardiac surgery when the heart is isolated from thecirculatory system. The pulsatile cardioplegia delivery can be used todose the cardioplegia into the coronary sinus in an amount that is atleast partially based upon pressure measurements in the coronary sinus.Furthermore, the catheter device can be employed to control the bloodflow through the heart after the heart is reconnected (unclamped) withthe circulatory system. As such, the initial blood flow though the heartmuscle tissue can be limited in a controlled manner that reduces thelikelihood of reperfusion injury to the heart muscle tissue that mightotherwise occur if full normal blood flow was immediately restored. Suchtreatment tasks provided by the catheter while the balloon is inflatedin the coronary sinus can lead to improved heart muscle tissue recoveryafter the cardiac surgery is completed and arterial blood flow returnsto the heart muscle tissue.

In other embodiments, the catheter system described herein can beemployed in an off-pump cardiac surgery in which the heart itself isproviding the circulation (e.g., not a blood pump of a heart-lungmachine). In such circumstances, the catheter device can be positionedin the coronary sinus to provide PICSO treatment to the heart. Further,the catheter device can include a lumen that selectively deliversretroperfusion blood into the coronary sinus (e.g., in the event of asudden reduction in coronary sinus pressure). The blood delivered intothe coronary sinus may comprise arterial blood that is sampled from amajor artery or an external source of oxygenated blood. Such a processcan be useful, for example, in cardiac surgeries when the heart islifted in a pericardial cradle to allow surgical access to the posterioraspect of the heart (e.g., during coronary artery bypass in an off-pumpcardiac surgery, or the like).

In alternative embodiments, the catheter system described herein can beused in a percutaneous coronary intervention (PCI) procedure. In suchcircumstances, the catheter device may be delivered percutaneouslythrough the venous system and into the coronary sinus. The catheterdevice can provide PICSO treatment to the heart during the PCI procedurethat is occurring in a different region of the heart. Also, the catheterdevice can include a lumen that selectively delivers retroperfusionblood into the coronary sinus (e.g., during a PCI procedure in which alonger period of perfusion deficit may occur). As previously described,the blood delivered into the coronary sinus may comprise arterial bloodthat is sampled from a major artery or an external source of oxygenatedblood.

In some embodiments, a coronary sinus occlusion catheter may include adistal tip portion including an inflatable balloon device configured toengage an interior wall of a coronary sinus when inflated. The cathetermay also include a distal port arranged distally of the inflatableballoon device so that the distal port extends into the coronary sinuswhen the inflatable balloon device is inflated in the coronary sinus.The catheter may further include an outflow port arranged proximally ofthe inflatable balloon device so that the outflow port is in fluidcommunication with the right atrium when the inflatable balloon deviceis inflated in the coronary sinus. The distal tip portion may at leastpartially define a fluid flow path from the distal port to the outflowport. The catheter may also include an inner movable member positionedin the flow path from the distal port to the outflow port. The innermovable member may be adjusted between a first position in which theflow path from the distal port to the outflow port is occluded and asecond position in which the flow path from the distal port to theoutflow port is open.

Particular embodiments described herein may include a method of treatingheart tissue during a cardiac surgery. The method may include, prior toisolating a heart from a circulatory system in the body, advancingdistal tip portion of a coronary sinus occlusion catheter into thecoronary sinus so that a stabilization balloon device of the coronarysinus occlusion catheter engages with an interior wall of the coronarysinus. The method may also include preconditioning heart muscle tissueby intermittently occluding the coronary sinus using the coronary sinusocclusion catheter to redistribute venous blood flow into the heartmuscle tissue while the stabilization balloon device continuouslyremains in an inflated condition in the coronary sinus. The method mayfurther include, after isolating the heart from the circulatory systemin the body, delivering a cardioplegia solution through a lumen of thecoronary sinus occlusion catheter and into the coronary sinus while thestabilization balloon device continuously remains in an inflatedcondition in the coronary sinus. The method may also include, after theheart is reconnected to the circulatory system in the body,intermittently occluding the coronary sinus using the coronary sinusocclusion catheter to redistribute venous blood flow into heart muscletissue while the stabilization balloon device continuously remains in aninflated condition in the coronary sinus.

In some embodiments, a system for cardiac surgery may include a coronarysinus occlusion catheter and a heart-lung machine. The catheter mayinclude a distal tip portion, a proximal hub portion, a stabilizationballoon device positioned along the distal tip portion and configuredengage an interior wall of a coronary sinus when in an inflatedcondition, and an inner movable member that is adjustable between afirst position and a second position for pressure-controlledintermittent coronary sinus occlusion. The heart-lung machine mayinclude a plurality of lines coupled to the proximal hub portion of thecoronary sinus occlusion catheter, and a control system to controlmovement of the inner movable member of the coronary sinus occlusioncatheter. The control system of the heart-lung machine may be used toadjust the inner movable member between the first position in which aflow path from the coronary sinus to a right atrium is occluded and thesecond position in which the flow path from the coronary sinus to theright atrium is open.

In particular embodiments, a coronary sinus occlusion catheter mayinclude a distal tip portion including an inflatable balloon deviceconfigured to engage an interior wall of a coronary sinus when in aninflated condition. The catheter may also include a first pressuresensor lumen extending to a distal position that is distal of theinflatable balloon device for detecting a first pressure. The cathetermay further include a second pressure sensor lumen extending to aproximal position that is proximal of the inflatable balloon device fordetecting a second pressure. The first pressure sensor lumen and thesecond pressure sensor lumen may be positioned relative to one anothersuch that a difference between the first pressure and the secondpressure is indicative of a flow rate of blood passing along the distaltip portion from a region distal of the balloon device to a regionproximal of the balloon device.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a system for treating heart tissue, inaccordance with some embodiments.

FIG. 2 is a perspective view of a portion of the system of FIG. 1.

FIGS. 3-4 are side views of a distal portion of a catheter device of thesystem of FIG. 1, when intermittently occluding a vessel.

FIG. 5 is a cross-sectional view of a shaft portion the catheter deviceof FIG. 4.

FIG. 6 is distal end view of a tip portion the catheter device of FIG.4.

FIGS. 7-8 are side views of the distal portion of the catheter device ofthe system of FIG. 1, when delivering cardioplegia.

FIGS. 9-10 are side views of a distal portion of an alternative catheterdevice for use with the system of FIG. 1.

FIG. 11 is a chart of a process for treating heart tissue during acardiac surgery, in accordance with some implementations.

FIG. 12 is a perspective view of the catheter device of FIGS. 1-8, in analternative system for use during an off-pump cardiac surgery or a PCIprocedure.

FIG. 13 is a diagram of a control circuitry for use in combination witha catheter device, in accordance with some embodiments.

FIG. 14 is a side view of a distal portion of the catheter device ofFIG. 4 used for intermittently occluding a vessel and determining ablood flow rate, in accordance with some embodiments.

FIGS. 15-16 are side views of a distal portion of an alternativecatheter device used for intermittently occluding a vessel anddetermining a blood flow rate, in accordance with particularembodiments.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

Referring to FIGS. 1-2, some embodiments of a system 100 for treatingheart tissue can include a coronary sinus occlusion catheter 120 and aheart-lung machine 102 (FIG. 1). The heart-lung machine 102 can operateas a perfusion system in which blood is oxygenated via an extracorporealcircuit during a cardiac surgery. As described in more detail below, theheart-lung machine 102 can house a catheter control system 160 that isconfigured to control the operation of the catheter 120 while a distalportion 121 of the catheter 120 is positioned in a vessel of the heart10 (e.g., the coronary sinus 20 in the depicted embodiment). Thecoronary sinus occlusion catheter 120 includes the distal portion 121(leading to a distal end depicted in FIG. 2) and a proximal portion 131,which includes a proximal hub 132 that is coupled to the heart-lungmachine 102 via a number of fluid or sensor lines 150, 153, 154, 155,156, and 159. Accordingly, the heart-lung machine 102 (including thecatheter control system 160 housed therein) may be employed to operateone or more components at the distal tip portion 121 of the coronarysinus occlusion catheter 120 while also receiving one or more sensorsignals that provide data indicative of heart characteristics (e.g.,coronary sinus pressure, right atrium pressure of fluid flow, and thelike).

Briefly, in use, the distal tip portion 121 of the coronary sinusocclusion catheter 120 can be arranged in a coronary sinus 20 of a heart10 as part of a cardiac surgery in which the heart 10 will be isolated(e.g., clamped off) from the circulatory system. The catheter 120 can beadvantageously employed to perform a number of functions before, during,and/or after the primary cardiac surgery (e.g., heart valve replacement,coronary bypass, or the like)—some or all of which can be performedwhile a balloon device 122 of the catheter 120 remains inflated in thecoronary sinus 20. For instance, the catheter 120 can be readily used toprecondition heart muscle tissue before the heart is isolated (orclamped off) from the circulatory system by providing PICSO treatment tothe heart 10 so as to precondition the heart muscle tissue withredistributed venous blood flow. When the catheter 120 is activated tointermittently occlude the blood flow exiting from the coronary sinus 20and into the right atrium 11, the venous blood flow that is normallyexiting from the coronary sinus 20 may be redistributed into a portionof heart muscle tissue 30 to precondition or pre-treat that heart muscletissue for the subsequent receipt of retrograde cardioplegia. Thus,while the portion of heart muscle tissue 30 normally receives blood flowfrom a coronary artery 40 and a local artery 41, the heart muscle tissue30 will receive redistributed blood from the venous side (e.g., from thelocal vein 21 or other branch veins 22) while the coronary sinus 20 isintermittently occluded with the catheter 120. During a subsequentperiod of time in which the heart 10 is isolated from the circulatorysystem, the catheter 120 can be employed to deliver cardioplegia (e.g.,pulsatile retrograde cardioplegia in particular embodiments) into thecoronary sinus 20. The control system 160 housed in the heart-lungmachine 102 can be configured to detect the pressure in the coronarysinus 20 and to thereafter determine an amount of cardioplegia thatshould be delivered through the catheter 120 and into the coronary sinus20 based at least in part upon the pressure measurements of the coronarysinus 20. During yet another subsequent period of time in which theheart 10 is reconnected to the circulatory system (e.g., the clamp isremoved to restore normal blood flow), the catheter 120 can control theblood flow through the heart 10 in order to limit any damage that mightotherwise be caused during the initial reperfusion of normal blood flowthrough the heart muscle tissue.

Still referring to FIGS. 1-2, the control system 160 (FIG. 1) housed inthe heart-lung machine 102 can be configured to provide automatedcontrol for both the inflatable balloon device 122 (which acts as astabilization balloon in the coronary sinus 20) and an occlusioncomponent (e.g., a movable inner member 140 (FIG. 3) of the catheter120). As described in more detail below, the control system 160 includescontrol circuitry 162 having a computer processor (refer to FIG. 13)that executes computer-readable instructions stored on at least onecomputer memory device (refer to FIG. 13) so as to activate ordeactivate the occlusion in the coronary sinus 20 in accordance withparticular patterns. For instance, the control system 160 can beconfigured to activate the occlusion component of the catheter 120 inthe coronary sinus 20 as part of a predetermined pattern of occlusionperiods and release periods that is independent of the coronary sinuspressure, or as part of a pressure-dependent pattern that is at leastpartially defined by the coronary sinus pressure readings during theprocedure. In addition, the heart-lung machine 102 is equipped with adisplay device 119 having a graphical user interface (e.g., a touchscreen display device) that provides a surgeon or other user withtime-sensitive, relevant data indicative of the progress of a coronarysinus occlusion procedure, a cardioplegia delivery procedure, and thecondition of the heart 10. As such, the user can view the graphical userinterface device 119 to readily monitor the heart's condition and theeffects of (i) intermittently occluding the coronary sinus 20 or (ii)delivering cardioplegia to the coronary sinus 20.

The distal tip portion 121 of the coronary sinus occlusion catheter 120can be delivered through the heart wall and positioned in the coronarysinus 20 so that the stabilization balloon 122 can be inflated in thecoronary sinus 20. The stabilization balloon 122 can be positionproximate to the ostium on the coronary sinus 120 so that a distal tipport 129 is located in the coronary sinus while an outflow port 123 ispositioned in the right atrium 11 (or in fluid communication with theright atrium 11). As described in more detail below, an inner movablemember 140 of the catheter 120 can be adjusted (FIG. 3) relative to theoutflow port 123 so as to occlude the coronary sinus 20 and therebycause redistribution of the venous blood into the heart muscle tissue30. Also, the inner movable member 140 can be positioned (FIG. 4)relative to the outflow port 123 so as to open a blood flow path fromthe coronary sinus 20 and to the right atrium 11. Accordingly, thecontrol system 160 housed in the heart-lung machine 102 can beconfigured to adjust the position of the inner movable member 140 so asto provide intermittent occlusion of the coronary sinus 20 duringdifferent periods of the cardiac surgery. In such circumstances, thestabilization balloon device 122 can remain inflated in the coronarysinus occlusion catheter 120 during the cardiac surgery regardless ofwhether the coronary sinus is occluded or non-occluded.

Referring now to FIG. 1, the heart-lung machine 102 may include a numberof components that provide the extracorporeal circuit for deliveringoxygenated blood to the patient's circulatory system. For example, theheart-lung machine 102 may include a plurality of roller pumps 109, 110,111, and 112 that can be individually activated and controlled todeliver a controlled flow of fluids, such as cardioplegia or blood. Theheart-lung machine can also include an oxygenator circuit 115 having ablood reservoir tank, a centrifugal blood pump, a bubble remover, and anumber of sensors. A first blood flow line 116 for delivering oxygenatedblood can extend from the heart lung machine 102 and can be connected tothe aorta 16. A second blood flow line 117 that returns venous blood tothe heart-lung machine 102 can be connected to the superior vena cava17, the inferior vena cava, or both. An internal control system of theheart lung machine (which may be separate from or incorporated with thecontrol system 160) can be used to monitor the blood sensors and thepatient's conditions so as to provide an ample supply of oxygenatedblood to the patient's circulatory system when the heart 10 is clampedoff from the circulatory system.

The proximal portion 131 of the coronary sinus occlusion catheter ispositioned external to the patient while the distal tip portion 121 isadvanced into the coronary sinus 20. The proximal portion 131 includesthe proximal hub 132 that is coupled to the heart-lung machine 102 via aset of fluid or sensor lines 150, 153, 154, 155, 156, and 159. As such,the control system 160 housed in the heart-lung machine 102 can inflateor deflate the stabilization balloon 122 and also adjust the position ofthe inner movable member 140 while contemporaneously receiving aplurality of sensor signals that provide data indicative of heartcharacteristics (e.g., coronary sinus pressure, right atrial pressure offluid flow, and the like).

In one example, the first line 150 extending between the control system160 and the proximal hub 132 comprises an actuation line for adjustingthe position of the inner movable member 140 at the distal portion 121of the catheter 120. The first line 150 is connected to a correspondingport 101 of the heart-lung machine 102 so that the line 150 is connectedwith the control system 160 housed in the heart-lung machine 102. Insome embodiments, the inner movable member 140 extends proximally fromthe distal portion 121 and through the proximal hub 132 and theactuation line 150 so that an actuator 165 (e.g., a pump, a motor, amagnetic actuator, a pneumatic actuator, or the like) housed in theheart-lung machine 102 can directly adjust the position of the innermovable member 140. Alternative, the proximal hub 132 can join theactuation line 150 with an actuation lumen 139 (FIG. 5) of the catheter120 so that the actuator 165 housed in the heart-lung machine 102 candeliver an actuation force (e.g., via a fluid pressure force, apush-pull cable, an electric signal that generates a magnetic force at acoil along the distal portion, or the like) to drive the movement of theinner movable member 140.

In another example, the second line 153 extending between the controlsystem 160 and the proximal hub 132 comprises an inflation-deflationline through which pressurized fluid (e.g., helium, another gas, or astable liquid) can be delivered to inflate the stabilization balloondevice 122 (and can be evacuated to deflate the balloon device 122). Theinflation-deflation line 153 is connected to a corresponding port 103 ofthe inflation-deflation so that the line 153 is in fluid communicationwith a pneumatic subsystem of the control system 160 housed in theheart-lung machine 102. The proximal hub 132 joins theinflation-deflation line 153 with a balloon control lumen 133 (FIG. 5)extending through the coronary sinus occlusion catheter 120 to a set ofports at the interior of the balloon device 122.

In another example, the third line 154 extending between the heart-lungmachine 102 and the proximal hub 132 comprises a balloon sensor linethat is in fluid communication with the interior of the balloon device122 so as to measure the fluid pressure within the balloon device 122.The proximal hub 132 joins the second line 154 with a balloonpressure-monitoring lumen 134 (FIG. 5) extending through the coronarysinus occlusion catheter 120 to a second set of ports at the interior ofthe balloon device 122. The pressure of the balloon device 122 may bemonitored by the control circuitry 162 (FIG. 1) of the control system160 as part of a safety feature that is employed to protect the coronarysinus 20 from an overly pressurized balloon device. The balloon sensorline 154 is connected to a corresponding port 104 of the heart-lungmachine 102 so that a pressure sensor arranged within the control system160 can detect the fluid pressure in the balloon device 122.Alternatively, a pressure sensor may be arranged in the distal tipportion 121 or in the proximal hub 132 such that only a sensor wireconnects to the corresponding port 104 of the heart-lung machine 102.

The proximal hub 132 also connects with a fourth line 155 extending fromthe heart-lung machine 102. The fourth line 155 comprises a coronarysinus pressure line that is used to measure the fluid pressure in thecoronary sinus 20 both when occluded and non-occluded. The proximal hub132 joins the fourth line 155 with a coronary sinus pressure lumen 135(FIGS. 5-6) extending through the coronary sinus occlusion catheter 120and to the distal port 129 that is distally forward of the balloondevice 122. As such, the coronary sinus pressure lumen 135 and at leasta portion of the third line 155 may operate as a fluid-filled pressuretransmission path (e.g., saline, another biocompatible liquid, or acombination thereof) that transfers the blood pressure in the coronarysinus 20 to a pressure sensor device 107 along a proximal portion of thefourth line 155. The pressure sensor device 107 samples the pressuremeasurements (which are indicative of the coronary sinus pressure) andoutputs a sensor signal indicative of the coronary sinus pressure to thecorresponding port 105 of the heart-lung machine 102 for input to thecontrol system 160. The coronary sinus pressure data may be displayed bythe graphical user interface 119 in a graph form so that a surgeon orother user can readily monitor the trend of the coronary sinus pressurewhile the coronary sinus 20 is in an occluded condition and in anon-occluded condition. Optionally, the graphical user interface 119 ofthe heart-lung machine 102 can also output a numeric pressuremeasurement on the screen so that the surgeon can readily view a maximumcoronary sinus pressure, a minimum coronary sinus pressure, or both. Inalternative embodiments, the pressure sensor device 107 can beintegrated into the housing of the heart-lung machine 102 so that thefourth line 155 is a fluid-filled path leading up to the correspondingport 105, where the internal pressure sensor device (much like thedevice 107) samples the pressure measurements and outputs a signalindicative of the coronary sinus pressure. Alternatively, the lumen 135may carry an optical fiber or wire that connects to a pressure sensingelement positioned at the distal opening of the lumen 135. As such, thepressure sensing element can be exposed to the fluid pressure at thedistal end of the lumen 135, and the optical fiber or wire cancommunicate the pressure sensor signal to the control system 160.

In yet another example, the fifth line 156 extending between theheart-lung machine 102 and the proximal hub 132 comprises a sensor linethat is employed to measure the fluid pressure or flow rate at the rightatrium 11. The proximal hub 132 joins the fifth line 156 with an atrialsensor lumen 136 (FIG. 5) extending through the coronary sinus occlusioncatheter 120 to a port that is exposed to the outflow port 123 proximalof the balloon device 122. In one example, the pressure in the rightatrium (e.g., the fluid exiting the outflow port 123 into the rightatrium) can be monitored by the control circuitry 162 (FIG. 1) of thecontrol system 160 so as to determine the blood flow rate from thecoronary sinus 20 into the right atrium 11. Namely, the pressuremeasured at the coronary sinus pressure lumen 135 (FIGS. 5-6) distallyof the balloon device 122 can be compared to the pressure at the atrialsensor lumen 136 (FIG. 5) so as to determine the blood flow rate throughthe flow path when the inner movable member 140 is in a non-occludingposition (FIG. 4). The fifth line 156 is connected to a correspondingport 106 of the heart-lung machine 102 so that a pressure sensorarranged within the control system 160 can detect the fluid pressure atthe outflow port 123 located in the right atrium 11. Alternatively, apressure sensor may be arranged in the distal end of the atrial sensorlumen 136 (FIG. 5) or the in the proximal hub 132 such that only asensor wire connects to the corresponding port 106 of the heart-lungmachine 102. For example, the lumen 136 may carry an optical fiber orwire that connects to a pressure sensing element positioned at thedistal opening of the lumen 136 (FIG. 5). As such, the pressure sensingelement can be exposed to the fluid pressure at the outflow port 123,and the optical fiber or wire can communicate the pressure sensor signalto the control system 160.

As shown in FIG. 1, in some embodiments a sixth line 159 may extend fromthe heart-lung machine 102 to the proximal hub so as to delivercardioplegia, blood, or another fluid through the catheter 120 and outof the distal port 129 (FIGS. 7-8). The fluid line 155 can extend fromone of the pumps 109, 110, 111, and 112 of the heart-lung machine 102and may include a bubble-removal tank 118 that reduces or eliminates anybubbles in the fluid. The proximal hub 132 joins the sixth line 155 withthe central lumen 130 (FIG. 5) which extends to the distal port 129positioned distally of the balloon device 122. As such, the heart lungmachine 102 can be operated to pump cardioplegia, blood, or anotherfluid through the central lumen 130 (FIG. 5) and out of the distal port129 for retrograde cardioplegia treatment or retroperfusion of blood(described below) when the heart 10 is isolated from the circulatorysystem.

Optionally, the system 100 may include one or more ECG sensors to outputECG signals to the control system 160 housed in the heart-lung machine102. For example, the ECG sensors can be connected to the control system160 via a cable that mates with a corresponding port along the housingof the heart-lung machine 102. As described in more detail below, theECG signals can be monitored during periods of the cardiac surgery bothbefore and after the cardioplegia is delivered to the heart (e.g., whilethe heart is actively beating). The ECG data can be displayed by thegraphical user interface 119 in a graph form so that a surgeon or otheruser can readily monitor the patient's heart rate and othercharacteristics (e.g., arterial pressure, aortic pressure, and the like)while the coronary sinus is in an occluded condition and in anon-occluded condition. Optionally, the graphical user interface 119 ofthe heart-lung machine 102 can also output numeric heart rate data basedon the ECG sensor data on the screen so that the surgeon can readilyview the heart rate (e.g., in a unit of beats per minutes). The ECGsensor signals that are received by the control system 160 are alsoemployed by the control circuitry 162 (FIG. 1) so as to properly timethe start of the occlusion period (e.g., the start time at which theinner movable member 140 is in the occlusion position (FIG. 3)) and thestart of the non-occlusion period (e.g., the start time at which theinner movable member 140 is in the non-occlusion position (FIG. 4)).

As previously described, some embodiments of the control system 160housed in the heart-lung machine 102 can include the control circuitry162 having the pneumatics subsystem. The control circuitry 162 caninclude one or more processors that are configured to execute varioussoftware modules stored on at least one memory device (refer, forexample, to FIG. 13). The processors may include, for example,microprocessors that are arranged on a motherboard so as to execute thecontrol instructions of the control system 160. The memory device mayinclude, for example, a computer hard drive device having one or morediscs, a RAM memory device, that stored the various software modules(refer, for example, to FIG. 13). In some embodiments, the controlcircuitry 162 can be configured to activate the actuator unit 165 of thecontrol system 160. As such, the control circuitry 162 can cause theactuator unit 165 to move the inner movable member 140 in a patternbased at least in part on the sensor signals indicative of the coronarysinus pressure (from the first sensor lumen 135 distal of the balloondevice 122) and the right atrium pressure (from the second sensor lumen136 proximal of the balloon device 122).

Referring now to FIGS. 3-4, the coronary sinus occlusion catheter 120can be configured to intermittently occlude the coronary sinus 20 whilethe inflatable balloon device 122 remains inflated in the coronary sinus20. The inflatable balloon device 122 of the coronary sinus occlusioncatheter 120 may have a predetermined shape when in the inflatedcondition. In this embodiment, the inflatable balloon device 122includes a first conical portion 122 a narrowing down toward the distaldirection, a second conical portion 122 c narrowing down toward theproximal direction, and a small generally cylindrical rim portion 122 bwhich is arranged between the conical portions. The narrowed ends ofeach of the conical portions 122 a and 122 c are connected with thecatheter shaft so as to provide a seal that prevents gas leakage fromthe balloon device 122. In the inflated condition, the diameter of theballoon device 122 in the region of the cylindrical rim portion 122 bis, for example, between about 12 mm and about 22 mm, and preferablyabout 15 mm. In some embodiments, the coronary sinus occlusion catheter120 can be equipped with a marker band positioned inside the balloondevice 122 and a second marker band near the distal port 129, each ofwhich comprises an X-ray compatible material so as to be renderedvisible during a surgery by suitable imaging processes.

As shown in FIG. 3, the inner movable member 140 of the catheter 120 canbe arranged at a first position in which a fluid flow path between thedistal port 129 and the outflow port 123 is blocked. As such, thecoronary sinus 20 is in an occluded state when the inner movable member140 is in the first position. The inner movable member 140 includes anopening 143 along a circumferential wall, which can be non-aligned withthe outflow port 123 (refer to FIG. 3) or aligned with the outflow port123 (refer to FIG. 4). When the opening 143 of the inner movable member140 is offset from the outflow port 123 along the shaft of the catheter120, the flow path between the distal port 129 and the outflow port 123is blocked, thereby causing the venous blood flow in the coronary sinus20 to be occluded. As such, the blood in the coronary sinus 20 isoccluded from passing from the coronary sinus 20 to the right atrium 11.As previously described, this redistribution of the venous blood flow inthe coronary sinus 20 can be employed to pre-condition the heart muscletissue prior to delivering retrograde cardioplegia to the coronary sinusvia the catheter 120. Further, the catheter device 120 can be used tolimit the blood flow through the heart muscle tissue (draining from thecoronary sinus 20 and into the right atrium 11) during the initialperiod after the heart 10 is reconnected to the circulatory system(after the heart is unclamped). The benefits from these procedures aredescribed in more detail below.

As shown in FIG. 4, the position of the inner movable member 140 can beadjusted by a motion 145 so that the opening 143 is generally alignedwith the outflow port 123 in the wall of the catheter 120. In suchcircumstances, the flow path between the distal port 129 and the outflowport 123 is opening, and blood is permitted to flow from the coronarysinus 20 and into the right atrium 11. As previously described, themovement of the inner movable member 140 in the catheter body can becontrolled by be control system 160 housed in the heart-lung machine 102(FIG. 1). For example, the actuator unit 165 of the control system 160can provide a driving force that acts upon the inner movable member 140to reciprocate the inner movable member between the first position (FIG.3) and the second position (FIG. 4). The inner movable member 140 mayslide along two or more seals 142 arranged inside the central lumen 130(FIG. 5) of the catheter 120. (It should be noted that the seals 142 arenot drawn to scale in FIGS. 3-4 and are enlarged for purposes ofillustration.)

Accordingly, the inner movable member 140 can act as a valve that ispositioned proximal to the stabilization balloon 122 and can becontrolled to intermittently occlude the coronary sinus 20. Thus, whilethe stabilization balloon 122 remains continuously inflated in thecoronary sinus 20, the inner movable member 140 can be controlled tointermittently move between the first position (FIG. 3) and the secondposition (FIG. 4) so as to cause the previously described redistributionof venous blood flow while also preventing the pressure in the coronarysinus from reaching unsafe levels. In particular embodiments, thecontrol system 160 housed in the heart-lung machine 102 (FIG. 1) canactuate the inner movable member 140 according to one of two types ofoperations: (i) a predetermined pattern of intermittent coronary sinusocclusion (time periods are independent of coronary sinus pressuremeasurements), or (ii) a pressure-controlled intermittent coronary sinusocclusion (time periods are dependent upon the coronary sinus pressuremeasurements). For example, during an initial phase when the catheter120 is first delivered into the coronary sinus 20 and initiallyactivated to pre-condition the heart tissue prior to receivingcardioplegia, the control system 160 can cause the inner movable member140 to reciprocate between the first and second positions according tothe predetermined pattern of occlusion times and non-occlusion times.During these time periods in the initial phase, the coronary sinuspressure measurements are recorded by the control system 160 (andoptionally displayed on the user interface display device 119), but thetime periods for the occluded state and the non-occluded state arepredetermined and do not change based upon the coronary sinus pressuremeasurements. After this initial phase, the control system 160 canautomatically switch the second type of operation in which the timeperiods for the occluded state and the non-occluded state are a functionof the previously recorded coronary sinus pressure measurements. Forexample, the control system 160 can cause the inner movable member 140to reciprocate between the first and second positions according to aPICSO algorithm that assesses a previous set of coronary sinus pressuremeasurements to thereby determine the new time period for the nextoccluded state or non-occluded state.

FIGS. 5 and 6 are different views of the distal portion 121 of thecatheter 120 depicted in FIG. 4. As shown in the cross-section view ofthe outflow port 123 and the inner movable member 140 (FIG. 5), theshaft of the catheter 120 can include a plurality of lumens 130, 133,134, 135, 136, and optionally 139. In this embodiment, the central lumen130 extends from the proximal hub 132 (FIG. 1) to the distal port 129(FIGS. 3-4) so as to provide fluid communication therethrough. The innermovable member 140 is positioned in the central lumen 130. For example,the inner movable member 140 can be a tubular piston device that isslidably positioned in the distal portion 121 of the catheter 120. Insuch circumstances, the catheter 120 may optionally include an actuatorlumen 139 that extends from the proximal hub 132 (FIG. 1) incommunication with the actuator line 150 (FIG. 1), so that the controlsystem 160 can deliver an actuation force to the inner movable member(e.g., via a fluid pressure force such as an internal inflatable balloonthat acts upon the inner movable member 140, a push-pull cable in thelumen 139 that that acts upon the inner movable member 140, an electricsignal delivered via the lumen 139 that provides a magnetic force uponthe inner movable member 140, or the like). In an alternative example,the inner movable member 140 may extend the entire length from thedistal portion (refer to FIGS. 3-4) to the control system 160 in theheart-lung machine 102. As such, there may be no need for the actuatorlumen 139, and the actuator unit 165 (FIG. 1) of the control system 160may act upon a proximal end of the inner movable member 140. In each ofthe aforementioned embodiments, the inner movable member 140 may have ahollow tubular shape so that an inner lumen 149 permits fluid flowingfrom the fluid line 159 (FIG. 1) through the central lumen 130 (e.g.,cardioplegia as shown in FIGS. 7-8) to pass through the inner movablemember 140 toward the distal port 129. However, during the periods whenthe catheter 120 is used to intermittently occlude blood flow from thedistal port 129 to the outflow port 123 (as previously described inconnection with FIGS. 3-4), the fluid line 159 (FIG. 1) may be clampedat a proximal location so that the blood flows out from the outflow port123 rather than advancing proximally through the central lumen 130 tothe fluid line 159.

Still referring to FIG. 5, the inflation-deflation lumen 133 of thecatheter 120 may be a ring segment-shaped lumen positioned radiallyoutward of the central lumen 130. The inflation-deflation lumen 133serves to supply and discharge fluid (e.g., helium gas in thisembodiment) for inflating and evacuating the balloon device 122.Accordingly, the inflation-deflation lumen 133 may extend from theproximal hub 132 (FIG. 1) to a first set of ports located at theinterior of the balloon device 122. The balloon pressure-monitoringlumen 134 may also be a ring segment-shaped lumen positioned radiallyoutward of the central lumen 130. The balloon pressure-monitoring lumen134 can be smaller than the inflation-deflation lumen 133 so that thering segment-shaped lumens 133 and 134 are different in sized. Theballoon pressure-monitoring lumen 134 extends from the proximal hub 132to a second set of ports located at the interior of the balloon device122 and serves to measure the fluid pressure within the balloon device122.

As shown in FIGS. 5-6, the coronary sinus pressure lumen 135 in thisembodiment is a ring segment-shaped lumen that extends fully to thedistal end of the catheter 120. The lumen 135 may be filled with abiocompatible fluid that is in fluid communication with the fluid in thecoronary sinus 20. Accordingly, the blood pressure in the coronary sinus20 is transferred to the fluid-filled path extending through the lumen135 and to the pressure sensor device 107 (FIG. 1). Alternatively, aminiature pressure sensor can be positioned at the distal end of thelumen 135 (FIG. 6) such that a sensor wire (e.g., electrical or optical)extends through the lumen 135 for communication with the control system160 (FIG. 1).

Referring again to FIG. 5, the shaft of the coronary sinus occlusioncatheter 120 includes the atrial sensor lumen 136, which is employed tomeasure either pressure or a flow rate at the outflow port 123,extending from the proximal hub 132 to a location adjacent to theoutflow port 123. The flow rate passing through the outflow port 123 andinto the right atrium 11 can be measured, for example, by detecting thefluid pressure at the outflow port 123. Then, the pressure measured atthe coronary sinus pressure lumen 135 (distally of the balloon device122) can be compared to the pressure at the atrial sensor lumen 136(proximal of the balloon device 122) so as to determine the blood flowrate through the flow path when the inner movable member 140 is in anon-occluding position (FIG. 4). The atrial sensor lumen 136 may operateas a fluid-filled lumen such that the blood pressure acts upon and istransferred through the fluid in the lumen 136 for detection by apressure sensor positioned outside the patient's body (e.g.,incorporated in the heart-lung machine 102). Alternatively, a pressuresensor transducer may be arranged in the distal end of the atrial sensorlumen 136 (FIG. 5) such that only a sensor wire connects extends throughthe sensor lumen 136 to the corresponding port 106 of the heart-lungmachine 102.

Referring now to FIGS. 7-8, the coronary sinus occlusion catheter 120can be configured to deliver a treatment fluid such as cardioplegia orwarm blood to the coronary sinus 20 while the inflatable balloon device122 remains inflated in the coronary sinus 20. As shown in FIG. 7, theinner movable member 140 of the catheter 120 can be adjusted to thefirst position in which the inner movable member 140 blocks the outflowport 123 is blocked. In such circumstances, the fluid line 159 (FIG. 1)can be established or unclamped so that there is a delivery path fromthe fluid line 159, through the proximal hub 132, through the centrallumen 130 and the inner lumen 149 of the inner movable member 140, andout of the distal port 129 into the coronary sinus 20. In someembodiments, the inner movable member 140 can be urged in the firstposition (in which the outflow port 123 is blocked) due to the treatmentfluid passing through the lumen 130 of the catheter and driving theinner movable member 140 in the distal direction to block the outflowport 123. In such cases, the inner movable member 140 can be adjusted tothe second position (to reopen the outflow port 123) when the heart-lungmachine 120 temporarily vents blood or other fluid from the lumen 130 ofthe catheter 120 and thereby urges the inner movable member 140 in aproximal direction. In addition or in the alternative, the position ofthe inner movable member 140 can be controlled by the control system 160before the treatment fluid is delivered through the lumen 130 and out ofthe distal port 129.

As previously described, the fluid that is dispensed into the coronarysinus 20 may be a cardioplegia solution, a warm blood supply that isused for retroperfusion (after cardioplegia delivery), or apharmaceutical agent employed to treat the heart muscle tissue. Such atreatment fluid can be driven through the catheter 120 by one or more ofthe roller pumps 109, 110, 111, and 112 of the heart-lung machine. Forexample, the heart-lung machine 102 can be configured to deliver thecardioplegia into the coronary sinus at a rate of about 180 ml/min toabout 220 ml/min, and preferably about the 200 ml/min. The time durationof the cardioplegia dispensation (and thus the amount of cardioplegia)can be at least partially based on the coronary sinus pressuremeasurements detected via the lumen 135 of the catheter 120. In anotherexample, the heart-lung machine 102 can be configured to deliver warmblood supply (e.g., retroperfusion blood) into the coronary sinus at arate of about 60 ml/min to about 470 ml/min, and preferably about 450ml/min. The flow rate of the retroperfusion blood can be adjusted towardpreferred rate of 450 ml/min, either manually or automatically under thecontrol of the control system 160, based at least in part on a pressuresensor measurement from a pressure sensor at the bubble-removal tank 118of the heart-lung machine 102.

In some embodiments, the control system 160 can be configured toautomatically adjust the amount of the treatment fluid that is deliveredinto the coronary sinus 20 in response to the coronary sinus pressuredata (e.g., the pressure sensor data from the lumen 135). For example,the heart-lung machine 102 can provide pulsatile retrograde cardioplegiainto the coronary sinus 20 in response to the pressure measurements inthe coronary sinus 20. This pressure-dependent process can be employedto control the amount of treatment fluid that is introduced into thecoronary sinus 20 so that the retroinfusion amount will be neither toolow nor too high. If the retroinfusion amount is too low, the venouspressure would be too low to ensure sufficient supply of the treatmentfluid is passing to portion 30 of the heart muscle tissue that mightotherwise develop into an ischemic region. If the retroinfusion amountis too high, the coronary venous pressure would increase at asubstantial rate and entail the risk of an overperfusion and causingirreversible damage to the vessel walls.

FIGS. 7-8 illustrate one example of an automated control of the fluiddelivery rate for the cardioplegia solution. In this example, thecontrol system 160 is configured to automatically control of the amountof cardioplegia that is delivered through the catheter 120 and into thecoronary sinus 20 as a function of at least one parameter derived fromthe coronary sinus pressure values measured via the lumen 135. Forinstance, if the pressure in the coronary sinus 20 is under a lowpressure condition (FIG. 7), the time duration of the cardioplegiadelivery (flowing at a constant 200 ml/min) may be relatively high so asto provide a high amount of cardioplegia flowing into the coronary sinus20. If the pressure in the coronary sinus is in a high pressurecondition, the time duration of the cardioplegia delivery (flowing at aconstant 200 ml/min) may be relatively low so that a lesser amount ofcardioplegia flows into the coronary sinus 20. In some embodiments, thepressure condition is not necessarily the absolute pressuremeasurements, but instead may be the time-derivative of the coronarysinus pressure measurements (e.g., the slope of the pressure curve). Insuch cases, if the time-derivative of the pressure measurement curveindicates that the pressure curve is rising at a higher rate (e.g., thepressure curve is not yet reaching a plateau level), the time durationof the cardioplegia delivery (flowing at a constant 200 ml/min) may berelatively high so as to provide a high amount of cardioplegia flowinginto the coronary sinus 20. If the time-derivative of the pressuremeasurement curve indicates that the pressure curve is rising at a lowerrate (e.g., the pressure curve is nearing a plateau level), the timeduration of the cardioplegia delivery (flowing at a constant 200 ml/min)may be relatively low so that a lesser amount of cardioplegia flows intothe coronary sinus 20.

Accordingly, the catheter 120 may serve a number of heart treatmentfunctions after the stabilization balloon device 122 is inflated in thecoronary sinus 20. As described in connection with FIGS. 3-4, thecatheter 120 can be used to precondition heart muscle tissue before theheart is isolated (or clamped) from the circulatory system. For example,the catheter 120 can provide PICSO treatment to the heart so as toprecondition the heart muscle tissue with redistributed venous bloodflow. As described in connection with FIGS. 7-8, the catheter 120 can beemployed to deliver cardioplegia and/or a supply of warm blood into thecoronary sinus during the cardiac surgery when the heart is isolatedfrom the circulatory system. The rate at which the cardioplegia orsupply of warm blood is delivered through the catheter 120 to thecoronary sinus 20 can be controlled by the heart-lung machine 102 basedat least in part upon pressure measurements of fluid in the coronarysinus 20. Furthermore, the catheter 120 can be employed to control theblood flow through the heart 10 after the heart 10 is reconnected(unclamped) with the circulatory system. Using the intermittentocclusion of the coronary sinus 20 as described in connection with FIGS.3-4, the initial blood flow though the heart muscle tissue can belimited in a controlled manner that reduces the likelihood of damage tothe heart muscle tissue that might otherwise occur if full normal bloodflow was immediately restored (e.g., reducing and, in some cases,reversing reperfusion injury).

Referring now to FIGS. 9-10, some alternative embodiments of thecoronary sinus occlusion catheter may include a different inner movablemember 240 than that which was previously described in connection withFIGS. 3-4. For example, the alternative catheter 120′ may be used withthe heart-lung machine 102 as illustrated in FIGS. 1-2, but the innermovable member 240 may be configured to partially rotate within thecatheter 120′ (rather than longitudinally reciprocate). As shown in FIG.9, the inner movable member 240 of the catheter 120′ can be adjusted toa first position in which a fluid flow path between the distal port 129and the outflow port 123 is blocked (because the inner movable member240 blocks the port 123). As such, the coronary sinus 20 is in anoccluded state when the inner movable member 240 is in the firstposition. The inner movable member 240 includes an opening 243 (FIG. 10)along a circumferential wall, which can be non-aligned with the outflowport 123 (refer to FIG. 9) or aligned with the outflow port 123 (referto FIG. 10). When the opening 243 of the inner movable member 240 isoffset from the outflow port 123, the flow path between the distal port129 and the outflow port 123 is blocked, thereby causing the venousblood flow in the coronary sinus 20 to be redistributed. As previouslydescribed, this redistribution of the venous blood flow in the coronarysinus 20 can be employed to pre-condition the heart muscle tissue priorto delivering retrograde cardioplegia to the coronary sinus via thecatheter 120′. Further, the catheter device 120′ can be used to limitthe blood flow through the heart muscle tissue (draining from thecoronary sinus 20 and into the right atrium 11) during the initialperiod after the heart 10 is reconnected to the circulatory system(after the heart is unclamped).

As shown in FIG. 10, the inner movable member 240 can be rotated aboutits longitudinal axis by a rotational motion 245 so that the opening 243is generally aligned with the outflow port 123 in the wall of thecatheter 120′. In such circumstances, the flow path between the distalport 129 and the outflow port 123 is opened, and blood is permitted toflow from the coronary sinus 20 and into the right atrium 11. Aspreviously described, the movement of the inner movable member 240 inthe catheter body can be controlled by be control system 160 housed inthe heart-lung machine 102 (FIG. 1). For example, the actuator unit 165of the control system 160 can provide a driving force that acts upon theinner movable member 240 to rotate the inner movable member between thefirst position (FIG. 9) and the second position (FIG. 10). The innermovable member 240 may slidably rotate along two or more seals 242arranged inside the central lumen of the catheter 120′. (It should benoted that the seals 242 are not drawn to scale in FIGS. 9-10 and areenlarged for purposes of illustration.)

Accordingly, the inner movable member 240 can act as a valve that ispositioned proximal to the stabilization balloon 122 and can becontrolled to intermittently occlude the coronary sinus 20. Thus, whilethe stabilization balloon 122 remains continuously inflated in thecoronary sinus 20, the inner movable member 240 can be controlled tointermittently rotate between the first position (FIG. 9) and the secondposition (FIG. 10) so as to cause the previously describedredistribution of venous blood flow while also preventing the pressurein the coronary sinus from reaching unsafe levels.

Referring now to FIG. 11, a process 300 for treating heart tissue duringa cardiac surgery can employ the previously described catheter 120 (or120′) in combination with a heart-lung machine 102. In particular, thecatheter 120 (or 120′) can be employed during a pre-conditioning phaseof the process 300 before the heart 10 is isolated from the circulatorysystem (e.g., before the aortic cross clamp is applied). Second, thecatheter 120 (or 120′) can be used to deliver cardioplegia, a supply ofwarm blood, or both during a second phase of the process 300 in whichthe heart is isolated from the circulatory system. Thirdly, the catheter120 (or 120′) can also be used in a third phase of the process 300 afterthe heart 10 is reconnected to the circulatory system to restore normalblood flow (e.g., after the aortic cross clamp is opened).

As shown in FIG. 11, the process includes a step 305 of pre-conditioningthe heart muscle tissue with a PICSO treatment. For example, thecatheter 120 (or 120′ can be used to provide PICSO treatment in whichthe coronary sinus 20 is intermittently occluded (e.g., occluded state,then non-occluded state, then occluded state, then non-occluded state,etc.) due to the movement of the inner movable member 140 (or 240). Asdescribed in connection with FIGS. 3-4 (or FIGS. 9-10), the controlsystem 160 housed in the heart-lung machine 102 can control theadjustment of the inner movable member 140 (or 240) based at least inpart on the coronary sinus pressure measurements detected via the lumen135. This step 305 of pre-conditioning the heart muscle tissue with thePICSO treatment can be initiated after the start of anesthesia butbefore the extracorporeal circuit (refer to FIG. 1) is started. Further,this step 305 may continue for a period of time until the aortic crossclamp is set to thereby isolate the heart from the circulatory system.

After the heart 10 is isolated from the circulatory system, the process300 may continue to a series of cardioplegia delivery steps 310, 315,320, and 325. In this embodiment, a cold cardioplegia solution isdelivered at steps 310 and 320 through the catheter 120 (or 120′) for aperiod of time. As previously described in connection with FIGS. 7-8,the cardioplegia delivery may be a pulsatile retrograde cardioplegiadelivery in which the rate of cardioplegia into the coronary sinus 20 isbased at least in part on the coronary sinus pressure measurementsdetected via the lumen 135. Each period of cold cardioplegia delivery310 and 320 is followed by a corresponding off period 315 and 325 inwhich no cardioplegia is delivered into the coronary sinus. During thesesteps 310, 315, 320, and 325, the cold cardioplegia solution may have alow temperature (e.g., about 4 degrees Celsius) so that the bloodtemperature of the heart 10 may be reduced. As a result, the heart 10may stop actively beating (e.g., cardiac arrest) so that the surgeon mayproceed to perform a primary surgical procedure such as a heart valvereplacement or a coronary bypass procedure. It should be understood fromthe description herein that the process 300 is not limited to the seriesof two cold cardioplegia delivery steps 310 and 320, but instead mayinclude a greater number of cold cardioplegia delivery steps in a largerseries. Furthermore, in some embodiments, the process 300 may include astep of taking a blood sample from the heart 10 after the completion ofeach cardioplegia delivery step 310 and 320. The blood sample can beused to determine the presence of a number of characteristics thatindicate whether there is a need for a further round or cardioplegia orother protection.

As shown in FIG. 11, the process 300 can include a step 330 ofdelivering a warm cardioplegia solution (e.g., a referred to herein as a“hot shot” of cardioplegia) through the catheter 120 (or 120′) and intothe coronary sinus 20 so as to initiate the process to warm the heartmuscle tissue. The warm cardioplegia solution may have a relativelyhigher temperature (e.g., about 37 degrees Celsius) so that the bloodtemperature of the heart 10 may be increased. As previously described inconnection with FIGS. 7-8, the warm cardioplegia delivery may be apulsatile retrograde cardioplegia delivery in which the rate of warmcardioplegia into the coronary sinus 20 is based at least in part on thecoronary sinus pressure measurements detected via the lumen 135.

In step 335, the process 300 includes delivering a supply of warm bloodthrough the catheter 120 (or 120′) and into the coronary sinus 20 so asto further the process of warming the heart muscle tissue. The warmblood may have a relatively higher temperature (e.g., about 37-38degrees Celsius) so that the blood temperature of the heart 10 may befurther increased toward the normal body temperature. As previouslydescribed in connection with FIGS. 7-8, the warm blood may be apulsatile retrograde cardioplegia delivery in which the rate of warmcardioplegia into the coronary sinus 20 is based at least in part on thecoronary sinus pressure measurements detected via the lumen 135.

After the heart 10 is reconnected to the circulatory system (e.g., afterthe aortic cross clamp is opened), the catheter device 120 (or 120′) mayremain in the coronary sinus 20 to provide further treatment to theheart 10. For example, the process 300 may include a step 340 ofreperfusing the heart with blood flow from the circulatory system whilethe blood flow rate is limited or controlled using a PICSO treatment or(other intermittent occlusion) from the catheter 120 (or 120′). Asdescribed in connection with FIGS. 3-4 (or FIGS. 9-10), the controlsystem 160 housed in the heart-lung machine 102 can control theadjustment of the inner movable member 140 (or 240) based at least inpart on the coronary sinus pressure measurements detected via the lumen135. As such, the full rate of normal blood supply is not applied to theheart muscle tissue when the heart 10 is reconnected with thecirculatory system. Instead, the blood flow rate through the heartmuscle tissue can be steadily increased or otherwise controlled so as toreduce the likelihood of damaging the heart muscle tissue with animmediate rush of blood flow from the arterial side. This step 340 ofproviding PICSO treatment after the heart 10 is reconnected to thecirculatory system can continue for a period of time even after theextracorporeal circulation is stopped (e.g., the heart-lung machine 102is no longer oxygenating the blood for the body).

Some embodiments of a system or method for treating heart tissue caninclude a multi-functional catheter device that provides a surgeon orother user with the ability to perform a number of heart treatment tasks(before, during, and after cardiac surgery) while a balloon deviceremains inflated in the coronary sinus. In particular, the catheterdevice can be readily used to precondition heart muscle tissue beforethe heart is isolated (or clamped) from the circulatory system. Forexample, the catheter device can be equipped to providepressure-controlled intermittent coronary sinus occlusion (PICSO)treatment to the heart so as to precondition the heart muscle tissuewith redistributed venous blood flow. Also, the catheter device can beemployed to deliver cardioplegia (e.g., pulsatile retrogradecardioplegia in particular embodiments) into the coronary sinus duringthe cardiac surgery when the heart is isolated from the circulatorysystem. The pulsatile cardioplegia delivery can be used to dose thecardioplegia into the coronary sinus in an amount that is at leastpartially based upon pressure measurements in the coronary sinus.Furthermore, the catheter device can be employed to control the bloodflow through the heart after the heart is reconnected (unclamped) withthe circulatory system. As such, the initial blood flow though the heartmuscle tissue can be limited in a controlled manner that reduces thelikelihood of damage to the heart muscle tissue that might otherwiseoccur if full normal blood flow was immediately restored. Such treatmenttasks provided by the catheter while the balloon is inflated in thecoronary sinus can lead to improved heart muscle tissue recovery afterthe cardiac surgery is completed and arterial blood flow returns to thepreviously blood-deprived portion of the heart muscle tissue.

Accordingly, the process 300 depicted in FIG. 11 provides a surgeon orother user with the ability to perform a number of heart treatment tasks(before, during, and after cardiac surgery) while the balloon device 122of the catheter 120 (or 120′) remains continuously inflated in thecoronary sinus 20. Before the start of the cardiac surgery (e.g., beforethe heart is isolated from the circulatory system), the catheter 120 (or120′) is used to precondition heart muscle tissue with a PICSO treatmentto the heart (to precondition the heart muscle tissue with redistributedvenous blood flow). During the cardiac surgery when the heart isisolated from the circulatory system, the catheter 120 (or 120′) is usedto deliver cardioplegia (e.g., pulsatile retrograde cardioplegia inparticular embodiments) and (optionally) a supply of warm blood into thecoronary sinus 20. After the cardiac surgery when the heart isreconnected (unclamped) with the circulatory system, the catheter 120(or 120′) can be employed to control the blood flow through the heartmuscle tissue (which can protect the heart muscle tissue from potentialdamage). Such treatment steps provided by the catheter 120 (or 120′)while the balloon device 122 is inflated in the coronary sinus 20 canlead to improved heart muscle tissue recovery after the cardiac surgeryis completed and normal blood flow returns to the heart muscle tissue.

Referring now to FIG. 12, some embodiments of the coronary sinusocclusion catheter 120 can be used in a PCI procedure or in an off-pumpcardiac surgery in which the heart itself is providing the circulation(e.g., not a blood pump of a heart-lung machine). In these embodiments,the catheter can be used to intermittently occlude the coronary sinus 20(e.g., by controlling the inner movable member 140 or 240 as describedin FIGS. 3-4 or FIGS. 9-10). Moreover, the catheter 120 can be used todeliver retroperfusion blood into the coronary sinus 20 when thestabilization balloon device 122 remains in the inflated condition(similar to the embodiments depicted in FIGS. 7-8).

For example, when the catheter 120 is used in a PCI procedure, thecatheter 120 may be delivered percutaneously through the venous system(e.g., through a guide member 108) and into the coronary sinus 20. Thecatheter 120 can provide PICSO treatment (by controlled movement of theinner movable member 140 or 240 as shown in FIG. 3-4 or 9-10) to theheart during the PCI procedure that is occurring in a different regionof the heart. Also, during the PCI procedure, the lumen 130 of thecatheter 120 that leads to the distal port 129 can be employed toselectively deliver retroperfusion blood into the coronary sinus 20.Such a feature may be useful, for example, during a PCI procedure inwhich a longer period of perfusion deficit may occur (e.g., duringpercutaneous valve procedures, during main stem stenting, or the like).The blood delivered through the lumen 130 of the catheter 120 and intothe coronary sinus 20 may comprise arterial blood that is sampled from amajor artery or an external source of oxygenated blood (e.g., a bloodreservoir, an oxygenated blood tank from a perfusion machine, or thelike). In some embodiments, the inner movable member 140 of the catheter120 can be urged in the first position (in which the outflow port 123 isblocked as shown in FIG. 3) due to the retroperfusion blood passingthrough the lumen 130 of the catheter 120 and driving the inner movablemember 140 in the distal direction to block the outflow port 123. Insuch cases, the inner movable member 140 can be adjusted to the secondposition (to reopen the outflow port 123) when some blood is vented fromthe lumen 130 of the catheter 120 to thereby urge the inner movablemember 140 in a proximal direction. In addition or in the alternative,the position of the inner movable member 140 can be controlled by acontrol system (described below) before the retroperfusion blood isdelivered through the lumen 130 and out of the distal port 129.

As shown in FIG. 12, the distal tip portion 121 of the coronary sinusocclusion catheter 120 can be arranged in a coronary sinus 20 of a heart10 and thereafter activated to intermittently occlude the blood flowexiting from the coronary sinus 20 and into the right atrium 11. Duringsuch an occlusion of the coronary sinus 20, the venous blood flow thatis normally exiting from the coronary sinus 20 may be redistributed intoa portion of heart muscle tissue 30 that has been damaged due to blooddeprivation or loss of functional myocardium. For example, the portionof heart muscle tissue 30 can suffer from a lack of blood flow due to ablockage 35 in a coronary artery 40. As a result, the arterial bloodflow to the affected heart muscle tissue 30 via a local artery 41 can besubstantially reduced such that the heart muscle tissue 30 becomesischemic or otherwise damaged. In some embodiments, the coronary sinusocclusion catheter 120 can be delivered into the coronary sinus 20 andthereafter activated so as to intermittently occlude the coronary sinus20 before, during, or after treating the blockage 35. Such an occlusioncan cause the venous blood flow to be redistributed to the local vein 21and then into the portion of heart muscle tissue 30 can suffer from alack of blood flow due to a blockage 35 in a coronary artery 40. Theischemic or otherwise damaged heart muscle tissue 30 can receive theredistributed venous blood flow for an improved the supply of nutrientsbefore, during, or after the blockage 35 is repaired or removed torestore normal coronary arterial blood flow.

In another example, when the catheter 120 is used in an off-pump cardiacsurgery, the catheter 120 can be positioned in the coronary sinus 120(e.g., preferably in a transatrial approach, but alternatively in apercutaneous delivery via a guide member 108) to provide PICSO treatmentto the heart. In particular, the catheter 120 can provide the PICSOtreatment by controlled movement of the inner movable member 140 or 240as shown in FIG. 3-4 or 9-10. Further, the lumen 130 of the catheter 120that leads to the distal port 129 can be used to selectively deliverretroperfusion blood into the coronary sinus (e.g., in the event of asudden reduction in coronary sinus pressure). The blood delivered intothe coronary sinus may comprise arterial blood that is sampled from amajor artery or an external source of oxygenated blood. Such a processcan be useful, for example, in cardiac surgeries when the heart islifted in a pericardial cradle to allow surgical access to the posterioraspect of the heart (e.g., during coronary artery bypass in an off-pumpcardiac surgery, or the like). As previously described, the innermovable member 140 of the catheter 120 can be urged in the firstposition (in which the outflow port 123 is blocked as shown in FIG. 3)due to the retroperfusion blood passing through the lumen 130 of thecatheter 120 and driving the inner movable member 140 in the distaldirection to block the outflow port 123. In such cases, the innermovable member 140 can be adjusted to the second position (to reopen theoutflow port 123) when some blood is vented from the lumen 130 of thecatheter 120 to thereby urge the inner movable member 140 in a proximaldirection. In addition or in the alternative, the position of the innermovable member 140 can be controlled by a control system (describedbelow) before the retroperfusion blood is delivered through the lumen130 and out of the distal port 129.

In these embodiments in which the catheter 120 is employed in anoff-pump cardiac surgery or a PCI procedure, the catheter 120 may becontrolled by a control system that operates similarly to the controlsystem 160 described in connection with FIG. 1. For example, the controlsystem may receives the inputs from the pressure sensing lumens 135 and136 and control the position of the inner movable member 140. Thecontrol system can be housed in a separate control module in the form ofa workstation computer or laptop computer that receives the connectionsfrom catheter's proximal lines or can be housed in the heart-lungmachine 102 as described in connection with FIG. 1 (even though thepumps of the heart-lung machine are not necessarily employed). Asdescribed in more detail below in connection with FIG. 13, the controlsystem can include a computer processor 163 that executescomputer-readable instructions stored on a computer memory device 166 orstorage device 167 so as to activate or deactivate the occlusion in thecoronary sinus 20 in accordance with particular patterns, which may bebased at least in part upon the coronary sinus pressure measurementsobtained via the lumen 135.

Referring now to FIG. 13, as previously described, the control systemfor controlling the coronary sinus occlusion catheter (such as thecontrol system 160 described in FIG. 1) can include control circuitry162 having one or more processors that executed software modules storedon one or more memory devices. It should be understood from thedescription herein that the control system 160 (or at least he controlcircuitry 162) can be housed in a heart-lung machine 102 as described inFIG. 1 or alternatively can be housed in a separate control module havethe form of a workstation computer or laptop computer. FIG. 13 is ablock diagram of one example of the control circuitry 162 that may beused to implement the systems and methods described in this document.For example, the control circuitry 162 may be used in the heart-lungmachine 102 (FIG. 1) or in a separate controller module in the form of aworkstation computer or laptop computer having instructions dedicatedfor the control of the catheter 120. The control circuitry 162 includesa processor 163, memory 166, a storage device 167, input and outputdevices 168 for connecting to data entry devices and graphical displays,and a bus system 169 that provides for communications between thesecomponents. The processor 163 can process instructions for executionwithin the control circuitry 162, including instructions stored in thememory 166 or on the storage device 167 to perform various operationsdescribed previously in this document. In addition, the componentsdescribed in this specification may also be implemented in firmware oron an application specific integrated circuit (ASIC), in which case thisFIG. 13 diagram is simply illustrative of device operation. The controlfeatures described herein may be implemented in digital electroniccircuitry, or in computer hardware, firmware, software, or incombinations of them. Also, the described control features may beimplemented advantageously in one or more computer programs that areexecutable on a programmable system including at least one programmableprocessor coupled to receive data and instructions from, and to transmitdata and instructions to, a data storage system, at least one inputdevice, and at least one output device.

Referring now to FIGS. 14-16, some embodiments of the catheter devicedescribed herein can be configured to monitor a flow rate of bloodpassing from the coronary sinus 20 to the right atrium 11, in additionto providing the capability to intermittently occlude the coronary sinus20 (e.g., PICSO treatment) or to deliver a treatment fluid (e.g.,cardioplegia or retroperfusion blood) into the coronary sinus 20. FIG.14 illustrate the embodiment of the catheter device 120 as previouslydescribed in connection with FIGS. 3-4 in which the inner movable member140 enables the catheter device 120 to intermittently occlude thecoronary sinus 20 (e.g., to provide PICSO treatment) while theinflatable balloon device 122 remains continuously inflated (e.g., astabilization balloon). FIGS. 15-16 illustrate an alternative catheterdevice 120″ in which the inflatable balloon device 122 is configured tointermittently adjust between a deflated condition (FIG. 16) and aninflated condition (FIG. 15) when positioned in the coronary sinus 20 soas to intermittently occlude the coronary sinus 20 (e.g., to providePICSO treatment). In both embodiments, the catheter device 120 or 120″can be equipped with a first pressure sensor lumen 135 or 135″ extendingto a distal position that is distal of the inflatable balloon device 122or 122″ (e.g. in the coronary sinus 20) and a second pressure sensorlumen 136 or 136″ extending to a proximal position that is proximal ofthe inflatable balloon device 122 or 122″ (e.g., in the right atrium11). As described in more detail below, the first pressure sensor lumen135 or 135″ and the second pressure sensor lumen 136 or 136″ arepositioned relative to one another such that a difference between afirst pressure (at 135 or 135″) and a second pressure (at 136 or 136″)is indicative of a flow rate of blood passing along the distal tipportion 121 or 121″ from a region distal of the balloon device 122 or122″ to a region proximal of the balloon device 122 or 122″.

As shown in FIG. 14, the catheter device 120 can include the distal tipportion 121 including the inflatable balloon device 122 configured toengage an interior wall of a coronary sinus 20 when in an inflatedcondition. As previously described in connection with FIGS. 1-4 and 12,the inflatable balloon device 122 operates as a stabilization balloonthat is configured to remain continuously inflated when blood passesalong the distal tip portion 121 from the region distal of the balloondevice 122 (e.g., from the distal port 129 in the coronary sinus 20) tothe region proximal of the balloon device 122 (e.g., to the outflow port123 in the right atrium 11). The distal port 129 is arranged distally ofthe inflatable balloon device 122 so that the distal port 129 extendsinto the coronary sinus 20 when the inflatable balloon device 122 isinflated in the coronary sinus 20. The outflow port 123 is arrangedproximally of the inflatable balloon device 122 so that the outflow port123 is in fluid communication with the right atrium 11 when theinflatable balloon device 122 is inflated in the coronary sinus. Also aspreviously described in connection with FIGS. 1-4 and 12, the distal tipportion 121 in this embodiment at least partially defines a fluid flowpath from the distal port 129 to the outflow port 123, and the innermovable member 140 can be positioned in the flow path so that the innermovable member 140 is adjustable between a first position in which theflow path from the distal port 129 to the outflow port 123 is occludedand a second position (shown in FIG. 14) in which the flow path is open.

The catheter device 120 can be equipped with first and second pressuresensing means for providing pressure data that is indicative of bloodflow from the coronary sinus 20 into the right atrium 11. For example,the catheter device 120 can include the first pressure sensor lumen 135(refer also to FIGS. 5-6) that extends to a position distal of theinflatable balloon device 122 for detecting a first pressure (e.g., ablood pressure in the coronary sinus 20). The catheter device 120 canalso include a second pressure sensor lumen 136 (refer also to FIG. 5)extending to a position proximal of the inflatable balloon device 122for detecting a second pressure (e.g., a blood pressure at the outflowport 123 into the right atrium 11). As shown in FIG. 14, the firstpressure sensor lumen 135 and the second pressure sensor lumen 136 arepositioned relative to one another such that a difference between thefirst pressure and the second pressure (e.g., ΔP) can be used as aparameter that is indicative a flow rate of blood passing along thedistal tip portion 121 from the coronary sinus 20 to the right atrium11.

For example, as shown in FIG. 14, the cross-section area of the flowpath of the blood can be estimated from the diameter (D1) of the fluidlumen 130 passing through the interior of the balloon device 122. Thiscross-sectional area can be a predetermined value that is input into thecontrol system for the catheter device 120. When the catheter device 120is in the non-occluded state and blood is flowing through the distalportion of the fluid lumen and outward from the outflow port 123, theflow rate of the blood can be readily determined by the controlcircuitry 162 (previous described). For example, signals indicative ofthe first pressure at the first pressure sensor lumen (Pressure 1) andthe second pressure at the second pressure sensor lumen 136 (Pressure 2)can be received by the control circuitry 162. From there, the controlcircuitry 162 can determine the blood flow rate based upon thecross-section area (known from the D1 measurement) and the pressuredifferential (ΔP=Pressure 1−Pressure 2). The flow rate value can becommunicated to the user, for example on a display screen of thegraphical user interface. This value for the volume flow rate can beuseful during a cardiac surgery or during a PCI procedure because it canserves as an indicator or prognostic parameter for myocardial perfusion.In particular, a higher value for the volume flow rate may indicate thatthe myocardial perfusion is better (e.g., improved likelihood of patientsurvival).

As shown in FIGS. 15-16, some alternative embodiments of the alternativecatheter device 120″ can include an inflatable balloon device 122 thatis configured to intermittently adjust between a deflated condition(FIG. 16) and an inflated condition (FIG. 15) when positioned in thecoronary sinus 20 so as to intermittently occlude the coronary sinus 20(e.g., to provide PICSO treatment). Similar to the previously describedembodiments, the catheter device 120″ can be equipped to measure thefirst pressure (distal of the balloon device 122″ in the coronary sinus20) and the second pressure (proximal of the balloon device 122″ in theright atrium 11) so that the flow rate of blood passing from thecoronary sinus 20 into the right atrium 11 can be determined andcommunicated to the user.

Similar to the previously described embodiments, the catheter device120″ can include the distal tip portion 121″ including the inflatableballoon device 122″ configured to engage an interior wall of a coronarysinus 20 when in an inflated condition. The catheter device 120″ canalso be equipped with first and second pressure sensing means forproviding pressure data that is indicative of blood flow from thecoronary sinus 20 into the right atrium 11. For example, the catheterdevice 120″ can include a first pressure sensor lumen 135″ (e.g., acentral lumen having a plurality of distal ports at a distal end) thatextends to a position distal of the inflatable balloon device 122″ fordetecting a first pressure (e.g., a blood pressure in the coronary sinus20). The catheter device 120″ can also include a second pressure sensorlumen 136″ (e.g., a non-central lumen having one or more ports along thecircumferential wall of the catheter shaft) extending to a positionproximal of the inflatable balloon device 122″ for detecting a secondpressure (e.g., a blood pressure near the balloon 122″ adjacent to theright atrium 11).

As shown in FIG. 15, when the balloon device 122″ is in the inflatedcondition and engages the coronary sinus 20, the blood flow from thecoronary sinus 20 to the right atrium 11 is occluded. Similar topreviously described embodiments, the catheter device 120″ can becoupled to a control system (having control circuitry 162) so as tointermittently adjust the balloon device 122″ to intermittently occludethe coronary sinus 20 based at least partially upon the coronary sinuspressure (e.g., measured via the sensor lumen 135″). Thus, as theballoon repeatedly shifts from the deflated condition (FIG. 16) to theinflated condition (FIG. 15), the catheter device 120″ is configured toprovide PICSO treatment to the heart.

As shown in FIG. 16, the first pressure sensor lumen 135″ and the secondpressure sensor lumen 136″ are positioned relative to one another suchthat a difference between the first pressure and the second pressure(e.g., ΔP) can be used as a parameter that is indicative a flow rate ofblood passing along the distal tip portion 121″ from the coronary sinus20 to the right atrium 11. For example, the cross-section area of theflow path of the blood (when the balloon device 122″ is deflated) can beestimated from the diameter (D2) of the coronary sinus 20 external to ofthe balloon device 122″. This measurement D2 can be measured, forexample, using an X-ray image, ultrasound imaging system, or otherimaging system and then input into the control system for the catheterdevice 120″. When the catheter device 120″ is in the non-occluded state(FIG. 16) and blood is flowing along the distal portion 121″, the flowrate of the blood can be readily determined by the control circuitry162. As previously described, signals indicative of the first pressureat the first pressure sensor lumen (Pressure 1) and the second pressureat the second pressure sensor lumen 136 (Pressure 2) can be received bythe control circuitry 162. From there, the control circuitry 162 candetermine the blood flow rate based upon the cross-section area (knownfrom the D1 measurement) and the pressure differential (ΔP=Pressure1−Pressure 2). The flow rate value can be communicated to the user, forexample on a display screen of the graphical user interface. Aspreviously described, this value for the volume flow rate can be usefulduring a cardiac surgery or during a PCI procedure because it can servesas an indicator or prognostic parameter for myocardial perfusion. Inparticular, a higher value for the volume flow rate may indicate thatthe myocardial perfusion is better (e.g., improved likelihood of patientsurvival).

Thus, in the embodiments described herein, the first pressure sensorlumen 135 or 135″ can serve as a coronary sinus pressure lumen thatextends to an opening arranged distally of the inflatable balloon device122 or 122″, and the second pressure sensor lumen 136 or 136″ can serveas an atrial pressure sensor lumen that extends to an opening arrangedproximally of the inflatable balloon device 122 or 122″.

Further, it should be understood from the description herein that one orboth of the first pressure sensor lumen 135 or 135″ and the secondpressure sensor lumen 136 or 136″ is configured to be a fluid-filledpressure transmission path that transfers a blood pressure to a pressuresensor transducer (e.g., a pressure transducer positioned in theproximal hub 132 or incorporated into the control circuitry 162).Alternatively, one or both of the first pressure sensor lumen 135 or135″ and the second pressure sensor lumen 136 or 136″ can include aminiature pressure sensor transducer positioned at a distal end of therespective lumen with an optical fiber or electric lead extending backthrough the lumen (e.g., for connection to the control circuitry 162).

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the scope of the invention. Accordingly,other embodiments are within the scope of the following claims.

1. A coronary sinus occlusion catheter, comprising: a distal tip portionincluding an inflatable balloon device configured to engage an interiorwall of a coronary sinus when in an inflated condition a first pressuresensor lumen extending to a distal position that is distal of theinflatable balloon device for detecting a first pressure; and a secondpressure sensor lumen extending to a proximal position that is proximalof the inflatable balloon device for detecting a second pressure,wherein the first pressure sensor lumen and the second pressure sensorlumen are positioned relative to one another such that a differencebetween the first pressure and the second pressure is indicative of aflow rate of blood passing along the distal tip portion from a regiondistal of the balloon device to a region proximal of the balloon device.2. The catheter of claim 1, wherein the inflatable balloon device isconfigured to intermittently adjust between a deflated condition and theinflated condition when positioned in the coronary sinus so as toprovide pressure-controlled coronary sinus occlusion.
 3. The catheter ofclaim 1, wherein the inflatable balloon device comprises a stabilizationballoon that is configured to remain continuously inflated when bloodpasses along the distal tip portion from the region distal of theballoon device to the region proximal of the balloon device.
 4. Thecatheter of claim 3, further comprising: a distal port arranged distallyof the inflatable balloon device so that the distal port extends intothe coronary sinus when the inflatable balloon device is inflated in thecoronary sinus; an outflow port arranged proximally of the inflatableballoon device so that the outflow port is in fluid communication withthe right atrium when the inflatable balloon device is inflated in thecoronary sinus, wherein the distal tip portion at least partiallydefines a fluid flow path from the distal port to the outflow port; andan inner movable member positioned in the flow path from the distal portto the outflow port, wherein the inner movable member is adjustedbetween a first position in which the flow path from the distal port tothe outflow port is occluded and a second position in which the flowpath from the distal port to the outflow port is open.
 5. The catheterof claim 4, further comprising a fluid delivery lumen extending from aproximal hub portion to the distal port that is arranged distally of theinflatable balloon device, wherein the fluid delivery lumen isconfigured to deliver cardioplegia or blood into the coronary sinus whenthe inflatable balloon device is inflated in the coronary sinus.
 6. Thecatheter of claim 4, wherein the proximal hub portion is connectable toa plurality of fluid or sensor lines extending from a heart-lungmachine.
 7. The catheter of claim 6, wherein the inner movable member isadjustable in response to a control system of the heart-lung machinethat causes the inner movable member to shift between the first positionand the second position.
 8. The catheter of claim 7, wherein the innermovable member is adjusted to the first position to occlude the coronarysinus for periods of time determined by the control system of theheart-lung machine, the periods of time for occluding the coronary sinusbeing at least partially based upon coronary sinus pressure measurementsreceived by the control system of the heart-lung machine via a coronarysinus pressure lumen of the coronary sinus occlusion catheter.
 9. Thecatheter of claim 4, wherein the inner movable member is repeatedlymovable between the first position and the second position so as tointermittently open blood flow from the coronary sinus to the atriumwhen the inflatable balloon device remains continuously inflated againstthe interior wall of the coronary sinus.
 10. The catheter of claim 1,further comprising a proximal hub portion, a balloon fluid lumenextending from the proximal hub portion to one or more openings that arearranged interior to the inflatable balloon device, and a balloonpressure-monitoring lumen extending from the proximal hub portion to oneor more openings that are arranged interior to the inflatable balloondevice.
 11. The catheter of claim 1, wherein the first pressure sensorlumen is a coronary sinus pressure lumen extending from the proximal hubportion to an opening that is arranged distally of the inflatableballoon device, and wherein the second pressure sensor lumen is anatrial pressure sensor lumen extending from the proximal hub portion toan opening that is arranged proximally of the inflatable balloon device.12. The catheter of claim 1, wherein at least one of the first pressuresensor lumen and the second pressure sensor lumen is configured to be afluid-filled pressure transmission path that transfers a blood pressureto a pressure sensor transducer.
 13. The catheter of claim 1, wherein atleast one of the first pressure sensor lumen and the second pressuresensor lumen includes a pressure sensor transducer positioned at adistal end of the at least one of the first pressure sensor lumen andthe second pressure sensor lumen.
 14. The catheter of claim 1, whereinthe catheter is configured to intermittently occlude the coronary sinuswhen the inflatable balloon device is inflated in the coronary sinusduring an off-pump cardiac surgery.
 15. The catheter of claim 14,further comprising a fluid delivery lumen extending from a proximal hubportion to the distal port that is arranged distally of the inflatableballoon device, wherein the fluid delivery lumen is configured todeliver retroperfusion blood into the coronary sinus when the inflatableballoon device is inflated in the coronary sinus during the off-pumpcardiac surgery.
 16. The catheter of claim 1, wherein the catheter isconfigured to intermittently occlude the coronary sinus when theinflatable balloon device is inflated in the coronary sinus during apercutaneous coronary intervention procedure.
 17. The catheter of claim16, further comprising a fluid delivery lumen extending from a proximalhub portion to the distal port that is arranged distally of theinflatable balloon device, wherein the fluid delivery lumen isconfigured to deliver retroperfusion blood into the coronary sinus whenthe inflatable balloon device is inflated in the coronary sinus duringthe percutaneous coronary intervention procedure.